With a liquid crystal display device, which is widely used as a display of a portable electronic appliance in recent years, after a wiring is formed, a semiconductor chip or a semiconductor device (hereinafter collectively referred to as a “semiconductor chip”) having the function of a drive circuit is mounted on a connection terminal that is provided at an edge portion of the wiring, by using an anisotropic conductive film (ACF). If it is determined at the time of inspection after mounting that the semiconductor chip is not normally operating, the mounted semiconductor chip has to be peeled off to be exchanged to another semiconductor chip. However, even after the semiconductor chip is peeled off, the ACF which was used at the time of pressure-bonding remains on the connection terminal. Accordingly, the ACF remaining on the connection terminal has to be thoroughly removed before another semiconductor chip is mounted.
At this time, if the adhesion between a metal film forming the connection terminal and an insulating film protecting the periphery of the connection terminal is poor, the insulating film around the connection terminal may be peeled off at the time of removing the ACF remaining on the connection terminal, and the reliability is reduced.
Patent Document 1 discloses forming a titanium nitride thin film on a gate electrode which is integrally formed with a scanning signal line, and improving the adhesion between the gate electrode and a gate insulating film. Because a connection terminal on which a semiconductor chip is to be mounted has the same structure as the gate electrode, the connection terminal is also tightly adhered to the gate insulating film.
Accordingly, an ACF remaining on the connection terminal after the semiconductor chip is peeled off may be removed in such a manner that an insulating film protecting the periphery of the connection terminal is not peeled off.